1. Technical Field
The present invention relates to the field of electrics, and more particularly, to an integrated circuit (IC) and a standby controlling method thereof.
2. Description of Related Art
In the deep sub-micron technology, static current leakage of integrated circuits (ICs) becomes increasingly serious, and the standby power consumption has become a hot topic universally concerned worldwide.
A standby mode of an IC means that the IC has been connected to an external power supply but the main function thereof is not in operation. The standby mode of an IC comprises two cases: one is that in the standby mode, some circuits in the IC preserve the operation status of the system before the standby mode so that when being waked up, the system can be restored into the previous status within a certain time; and the other is that the IC has already been in a reset status and after being enabled, the system cannot be restored into the status previous to the standby mode. For an IC with a power supply integrated therein, an external power supply can only provide a proper power supply voltage to some circuits in the IC.
The static current and the power supply voltage of the IC are in the exponential relationship, so in the deep sub-micron technology, for purpose of solving the static current leakage problem of the IC in the standby mode, a conventional method is to power off circuit devices that do not need to operate in the standby mode and have static current leakage, i.e, to stop operation of voltage regulators that provide power supplies to these circuit devices when the IC is in the standby mode. When the IC in the standby mode is required to operate the main function thereof, the voltage regulators in the off status are instantly enabled to generate a required stable voltage.
When the IC operates the main function thereof, power supplies needed by internal devices thereof all operate normally, so the IC can make a rapid response to a variation of an input signal or an internal signal; however, the static power consumption in this case is higher. When the IC is in the standby mode, at least some of the voltage regulators and some of the functional devices in the system stop operating, so the standby power consumption is lower; however, because only after the voltage regulators that stop operating are re-started and are able to output a stable power supply can the IC operate the main function thereof, the IC in the standby mode makes a slower response to the variation of the input signal or the internal signal.
FIG. 1 shows a general architecture of an IC having the standby function according to the prior art, wherein the IC has a power supply integrated therein. The IC 11 comprises a power supply control device 111, a reset device 112 and a functional device 113, and is connected to an external power supply 12 and a wake-up device 13. When the IC 11 is in a normal operation status, the power supply control device 111 makes conversion on a power supply voltage outputted by the external power supply 12 and provides the functional device 113 with a required power supply, which may represent either one power supply or a plurality of power supplies. Meanwhile, a clock generator in the reset device 112 provides a clock signal to the functional device 113, and the clock generator may either be integrated in the IC 11 or be disposed outside the IC 11 (i.e., generated by an external clock circuit). When the IC 11 enters into the standby mode from the normal operation status, the functional device 113 or an external circuit sends a system standby signal, which not only notifies the reset device 112 to generate a reset signal for resetting the functional device 113 and shield the clock signal but also turns off the power supply control device 111 (i.e., power off the functional device 113) in order to prevent static current leakage from occurring to the functional device 113. Of course, if the IC 11 requires one or more stable power supplies to still operate in the standby mode, then the system standby signal only turns off power supplies that do not need to operate in the standby mode; and in this case, although the standby power consumption of the IC 11 is somewhat increased, the functionality or performance of the IC 11 in the standby mode is significantly enhanced. When the IC 11 enters into the normal operation status from the standby mode, the wake-up device 13 generates a wake-up signal to start the power supply control device 111 instantly (i.e., re-start the power supplies that are turned off in the standby mode) to generate a required stable power supply. Meanwhile, the wake-up signal notifies the reset device 112 so that when the power supply generated by the power supply control device 111 comes into a stable status and a power supply stabilizing signal 94 is sent, the reset device 112 disables the reset signal and provides a clock signal to the functional device 113 to have the functional device 113 operate normally. The wake-up device 13 may either be disposed outside the IC 11 or be integrated in the IC 11.
A conventional standby method for the IC 11 is to reduce the static power consumption of the functional device 113 significantly by powering off all or some of the power supplies of the functional device 113 so as to ensure very low standby power consumption of the IC 11; however, when the IC 11 needs to be waked up (i.e., enter into the normal operation status from the standby mode), the functional device 113 can begin to operate normally only after the power supplies that are turned off in the standby mode are re-started and become stable, resulting a long wake-up time required by the IC 11.